Many photographic materials, particularly color negative films, contain so-called DIR (development inhibitor releasing) couplers. In addition to forming imaging dye, DIR couplers release inhibitors that can restrain silver development in the layer in which release occurs as well as in other layers of a multilayer photographic material. DIR couplers can help control gamma or contrast, can enhance sharpness or acutance, can reduce granularity and can provide color correction via interlayer interimage effects. There has been a need for more effective magenta dye-forming DIR couplers. Magenta DIR couplers that provide high interimage color correction are particularly desirable for modem color negative films. In addition, it is desirable that such couplers have high activity to maximize rates and efficiencies of inhibitor release and to minimize laydowns. It is also desirable that the magenta DIR couplers be stable toward long term storage particularly at elevated temperatures. The DIR couplers of this invention possess all of these desirable properties, particularly higher activity and greater stability than analogous magenta-dye forming DIR couplers of the prior art.
There are known pyrazolone couplers that contain an unsubstituted benzotriazole coupling-off group, which is outside the scope of the R.sub.8 and R.sub.9 substituents of this invention. U.S. Pat. No. 4,015,988 lists pyrazolone couplers (9 & 10) with methyl or bromo substituents. However, both couplers have o-methoxy substituents on the anilino group, which is outside the scope of the anilino substituents of this invention. JP60 128,444 discloses a coupler with a dimethyl-substituted benzotriazole, but this coupler also has an o-methoxy substituent on the anilino group.
Many of the prior art couplers, such as those in GB 1,455,967, have a p-nitro substituent on the 1-phenyl group that is outside the scope of the substituents of this invention. U.S. Pat. No. 4,477,563 deals generally with couplers, such as pyrazolone couplers, having benzotriazole leaving groups, but the exemplified couplers contain 2,4,6-trichloro substitution on the 1-phenyl ring or otherwise contain substituents which do not provide the desired improvement in reactivity.
A problem to be solved is to provide a photographic element comprising a silver halide emeulsion layer having associated therewith a magenta dye-forming coupler that has good reactivity and good raw stock keeping.